The present invention relates to a piezoelectric vibrator for use in devices such as portable telephones and portable information terminals.
As a conventional piezoelectric vibrator, there is known, for example, a structure shown in FIG. 8 having oscillation electrode films 63 for vibrating piezoelectric vibration pieces having one end connected to lead electrodes 62 provided on upper and lower surfaces of a piezoelectric vibration plate 61 integrally formed with a piezoelectric vibration piece and a frame portion, and a pair of lid members 66 bonded through bonding materials 64 on the oscillation electrode films 63 and each having a recess 65 defining such a degree of a space as not to prevent vibration of the piezoelectric vibration pieces.
In such a piezoelectric vibrator, generally the oscillation electrode films 63 are respectively extended from different longitudinal ends of the piezoelectric vibration plate 61 to a side surface and connected to lead electrodes 62. This lead electrode 62 is extended to a surface of one lid member 66.
However, in the above construction, a gap occurs between the piezoelectric vibration plate 61 and the lid member 66 at the vicinity of the lengthwise end of the piezoelectric vibration plate 61 on a surface opposite to a side from which the oscillation electrode film 63 extends. Due to this, a space A is formed at an inner side of the lead electrode 62. There is a problem that in this portion the lead electrode 62 is low in strength and hence there is a high possibility of disconnection.
The present invention has been made in view of such a circumstance, and it is an object to provide a piezoelectric vibrator in which the possibility of disconnection of a lead electrode is lowered and its reliability is improved.
In first form of the invention for solving the object, a piezoelectric vibrator comprises a piezoelectric vibration plate having a piezoelectric vibration piece and a frame portion connected integrally with a base portion thereof and surrounding the piezoelectric vibration piece; a pair of oscillation electrodes provided on opposite surfaces of the piezoelectric vibration plate to vibrate the piezoelectric vibration plate; and a pair of lid members which are bonded through bonding films and which are connected to face each of the oscillation electrodes for hermetically sealing the piezoelectric vibration piece without interfering vibration thereof; the pair of oscillation electrodes has a first electrode formed on a first one of the opposite surfaces of the piezoelectric vibration plate and extending lengthwise to one end of the piezoelectric vibration plate on the first surface, and a second electrode formed on the other of the opposite surfaces of the piezoelectric vibration plate and extending lengthwise to another end of the piezoelectric vibration plate on the second surface; and wherein at least one of the electrodes extends from one of the surfaces to the opposite surface of the piezoelectric vibration plate through a side surface of the end.
In a second form of the invention, the one pair of oscillation electrodes of both electrodes are extended to a surface on an opposite side through an end side surface on an extension side.
In a third form of the invention, the one pair of oscillation electrodes at lengthwise both ends are connected with face to face each lead electrode extended to a surface of the lid member on a side that at least one electrode is extended to a surface on an opposite side of the piezoelectric vibration plate.
In the invention as described above, it is possible to prevent disconnection of the lead electrode.